Sustainable System and Method for Removing and Concentrating Per- and Polyfluoroalkyl Substances (PFAS) from Water

ABSTRACT

A sustainable system for removing and concentrating per- and polyfluoroalkyl substances (PFAS) from water. The system includes an anion exchange vessel having a selected anion exchange resin therein configured to remove PFAS from the water. A line coupled to the vessel introduces a flow of water contaminated with PFAS such that the PFAS bind to the selected anion exchange resin and are thereby removed from the water. A regenerant solution line is coupled to the anion exchange vessel to introduce an optimized regenerant solution to the anion exchange vessel to remove the PFAS from the anion exchange resin, thereby regenerating the anion exchange resin and generating a spent regenerate solution comprised of the removed PFAS and the optimized regenerant solution. A separation and recovery subsystem recovers the optimized regenerant solution for reuse and separates and concentrates the removed PFAS.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/861,721 filed Apr. 29, 2020, and hereby claims benefit of andpriority thereto under 35 U.S.C. §§ 119, 120, 363, 365, and 37 C.F.R. §1.55 and 1.78, which is incorporated herein by reference, and is acontinuation of U.S. patent application Ser. No. 16/410,223 filed May13,2019 (now U.S. Pat. No. 11,027,988 issued Jun. 8, 2021), and herebyclaims benefit of and priority thereto under 35 U.S.C. §§ 119, 120, 363,365, and 37 C.F.R. § 1.55 and § 1.78, which is incorporated herein byreference, and U.S. patent application Ser. No. 16/410,223 filed May 13,2019 is a continuation of U.S. patent application Ser. No. 15/477,350filed Apr. 3, 2017 (now U.S. Pat. No. 10,287,185 issued May 14, 2019),and hereby claims benefit of and priority thereto under 35 U.S.C. §§119, 120, 363, 365, and 37 C.F.R. § 1.55 and § 1.78, which isincorporated herein by reference, and U.S. patent application Ser. No.15/477,350 claims benefit of and priority to U.S. ProvisionalApplication Ser. No. 62/321,929 filed Apr. 13, 2016, under 35 U.S.C. §§119, 120, 363, 365, and 37 C.F.R. § 1.55 and § 1.78, which is alsoincorporated herein by this reference.

FIELD OF THE INVENTION

This invention relates to a sustainable system and method for removingand concentrating per- and polyfluoroalkyl substances (PFAS) from water.

BACKGROUND OF THE INVENTION

Per- and polyfluoroalkyl substances (PFAS) are a class of man-madecompounds that have been used to manufacture consumer products andindustrial chemicals, including, inter alia, aqueous film forming foams(AFFFs). AFFFs have been the product of choice for firefighting atmilitary and municipal fire training sites around the world. AFFFs havealso been used extensively at oil and gas refineries for both firetraining and firefighting exercises. AFFFs work by blanketing spilledoil/fuel, cooling the surface, and preventing re-ignition. PFAS in AFFFshave contaminated the groundwater at many of these sites and refineries,including more than 100 U.S. Air Force sites.

PFAS may be used as surface treatment/codings in consumer products suchas carpets, upholstery, stain resistant apparel cookware, paper,packaging, and the like, and may also be found in chemicals used forchemical plating, electrolytes, lubricants, and the like, which mayeventually end up in the water supply.

PFAS are bio-accumulative in wildlife and humans because they typicallyremain in the body for extended periods of time. Laboratory PFASexposure studies on animals have shown problems with growth anddevelopment, reproduction, and liver damage. In 2016, the U.S.Environmental Protection Agency (EPA) issued the following healthadvisories (HAs) for perfluorooctanesulfonic acid (PFOS) andperfluorooctanoic acid (PFOA): 0.07 μg/L for both the individualconstituents and the sum of PFOS and PFOA concentrations, respectively.Additionally, PFAS are highly water soluble in water, result in large,dilute plumes, and have a low volatility.

PFAS are very difficult to treat largely because they are extremelystable compounds which include carbon-fluorine bonds. Carbon-fluorinebonds are the strongest known bonds in nature and are highly resistantto breakdown.

The vast majority of available conventional water treatment systems andmethods to remove PFAS from water have proven to be ineffective. Seee.g., Rahman, el al., Behaviour and Fate of Perfluoroalkyl andPolyfluoroalkyl Substances (PFASs) in Drinking Water Treatment, WaterResearch 50, pp. 318-340 (2014), incorporated by reference herein.Conventional activated carbon adsorption system and methods to removePFAS from water have shown to be somewhat effective on the longer-chainPFAS, but have difficulty in removing branched and shorter chaincompounds, see e.g. Dudley, Master's Thesis: Removal of PerfluorinatedCompounds by Powdered Activated Carbon, Superfine Powdered ActivatedCarbon, and Anion Exchange Resins, North Carolina State University(2012), incorporated by reference herein.

Appleman et al., Treatment of Poly- and Perfluoroalkyl Substances inU.S. Full-Scale Treatment Systems, Water Research 51, pp. 246-255(2014), incorporated by reference herein, reported that, similar toactivated carbon, some conventional anion exchange resins may be moreeffective at treating longer chain PFAS than the shorter chaincompounds. Other conventional anion exchange resins have shown somesuccess in removing a broader range of PFAS, including the shorter-chaincompounds, see e.g., Dudley, cited supra.

Conventional anion exchange treatment systems and methods typicallyutilize anion exchange resin where positively charged anion exchangeresin beads are disposed in a lead vessel which receives a flow of watercontaminated with anionic contaminants, such as PFAS. The negativelycharged contaminants are trapped by the positively charged resin beadsand clean water flows out of the lead anion exchange vessel into a lagvessel, also containing anion exchange resin beads. A sample tap isfrequently used to determine when the majority of the anion exchangebeads in the lead exchange vessel have become saturated withcontaminants. When saturation of the resin anion exchange beads isapproached, a level of contaminants will be detected in the effluenttap. When this happens, the lead vessel is taken off line and thecontaminated water continues flowing to the lag vessel which now becomesthe lead vessel. The lead-lag vessel configuration ensures that a highlevel of treatment is maintained at all times.

As discussed above, some conventional anion exchange resins can also beused to remove PFAS from water. A number of known methods exist toregenerate the anion exchange beads in the anion exchange vessel. Someknown methods rely on flushing the resin with a brine or causticsolution. Other known methods may include the addition of solvents, suchas methanol or ethanol, to enhance the removal of the PFAS trapped onthe anion exchange beads. Effective resin regeneration has beendemonstrated by passing a solvent (e.g., methanol of ethanol), blendedwith a sodium chloride or sodium hydroxide solution, through the resin.See e.g., Deng et al., Removal of Perfluorooctane Sulfonate fromWastewater by Anion Exchange Resins: Effects of Resin Properties andSolution Chemistry, Water Research 44, pp. 5188-5195 (2010) andChularueangaksorn et al., Regeneration and Reusability of Anion ExchangeResin Used in Perfluorooctane Sulfonate Removal by Batch Experiments,Journal of Applied Polymer Science, 10.1002, pp. 884-890 (2013), bothincorporated by reference herein. However, such methods may generate alarge amount of toxic regenerant solution which must be disposed of atsignificant expense.

Du et al., Adsorption Behavior and Mechanism of Perfluorinated Compoundson Various Adsorbents—A Review, J. Haz. Mat. 274. pp. 443-454 (2014),incorporated by reference herein, discloses a need to further treat thewaste regenerant solution to concentrate the PFAS and reduce the volumeof waste. This is a key step, because resin regeneration produces asignificant volume of toxic waste.

The known methods for removing PFAS from water discussed above typicallydo not optimize the anion exchange resin and may have limited capacityfor removing PFAS mass. Such known methods may also incompletelyregenerate the anion exchange resin by attempting to desorb the PFASfrom the resin. Such known methods may incompletely regenerate the anionexchange resin which may lead to a loss of capacity, otherwise known asactive sites, during each successive loading and regeneration cycle.This cumulative buildup of PFAS on the ion exchange resin is oftenreferenced to as a “heel,” and results in reduced treatmenteffectiveness as the heel builds up over time. Such known methods mayalso not reclaim and reuse the spent regenerant solution which mayincrease the amount spent regenerant solution with removed PFAS therein.This increases the amount of toxic spent regenerant solution with PFAS,which must be disposed of at significant expense.

Conventional systems and methods for attempting to remove PFAS alsoinclude biological treatment, air stripping, reverse osmosis, andadvanced oxidation. All of these conventional techniques are ineffectiveand/or extremely expensive.

BRIEF SUMMARY OF THE INVENTION

In one aspect, a sustainable system for removing and concentrating per-and polyfluoroalkyl substances (PFAS) from water is featured. The systemincludes an anion exchange vessel including a selected anion exchangeresin therein configured to remove PFAS from the water. A line coupledto the vessel is configured to introduce a flow of water contaminatedwith PFAS such that the PFAS bind to the selected anion exchange resinand are thereby removed from the water. A regenerant solution linecoupled to the anion exchange vessel is configured to introduce anoptimized regenerant solution to the anion exchange vessel to remove thePFAS from the anion exchange resin thereby regenerating the anionexchange resin and generating a spent regenerant solution comprised ofthe removed PFAS and the optimized regenerant solution. A separation andrecovery subsystem is configured to recover the optimized regenerantsolution for reuse and separate and concentrate the removed PFAS.

In one embodiment, the PFAS may be removed from the anion exchange resinby a dual mechanism including desorption and anion exchange. Thedesorption may include providing the optimized regenerant solutionhaving a predetermined concentration of a solvent configured to displaceadsorbed hydrophobic tails of PFAS from the backbone of the anionexchange resin with the solvent and providing a predeterminedconcentration of salt or base configured to displace hydrophilic headsof PFAS with inorganic anions. The optimized regenerant solution mayinclude a mixture of a salt or a base, a solvent, and water. The solventmay include an alcohol. The optimized regenerant solution may includeabout 50% to about 90% methanol by volume, about 10% to about 50% waterby volume, and about 1% to about 5% salt or base by weight. Theoptimized regenerant solution may include about 70% methanol by volume,about 28% water by volume, and about 2% salt or base by weight. Theselected anion exchange resin may include a macroporous, strong base,anion exchange resin. The separation and recovery subsystem may includeone or more of: an evaporation subsystem, a distillation subsystemand/or a membrane separation subsystem. The system may include acondenser coupled to the evaporation or distillation unit configured tocondense the reclaimed regenerant solution. The separation and recoverysubsystem may include a solvent purification subsystem configured toremove carryover PFAS from the separation and recovery subsystem and toprovide a purified, reclaimed solvent for reuse. The solventpurification subsystem may include anionic exchange resin housed in avessel. The separation and recovery subsystem may include asuper-loading recovery subsystem configured to create anultra-concentrated PFAS waste product and a solution of concentratedsalt or base and water for reuse. The super-loading recovery subsystemmay include an anionic exchange resin housed in a vessel. Thesuper-loading recovery subsystem may be configured to provide purifiedreclaimed water and purified reclaimed salt or base for reuse.

In another aspect, a sustainable method for removing and concentratingper- and polyfluoroalkyl substances (PFAS) from water is featured. Themethod includes selecting an anion exchange resin configured to removePFAS and provide treated water, adding the selected anion exchange resinto an anion exchange vessel, introducing a flow of water contaminatedwith PFAS to a vessel such that the PFAS bind to the selected anionexchange resin and are thereby removed from the water, introducing anoptimized regenerant solution to the anion exchange vessel to remove thePFAS from the anion exchange resin thereby regenerating the anionexchange resin and generating a spent regenerant solution comprised ofremoved PFAS and the optimized regenerant solution, and subjecting thespent regenerant solution to a separation and recovery process torecover the optimized regenerant solution for reuse and separate andconcentrate the removed PFAS.

In one embodiment, the PFAS may be removed from the anion exchange resinby a dual mechanism including desorption and anion exchange. Thedesorption may include providing a predetermined concentration of asolvent configured to displace hydrophobic tails of the PFAS on thebackbone of the union exchange resin with the solvent and providing apredetermined concentration of anions configured to displace hydrophilicheads of the PFAS with the anions. The optimized regenerant solution mayinclude a mixture of a salt or a base, a solvent, and water. The solventmay include an alcohol. The optimized regenerant solution may includeabout 50% to about 70% methanol by volume, about 2% to about 28% waterby volume, and about 1% to about 5% salt or base by weight. Theoptimized regenerant solution may include about 70% methanol by volume,about 28% water by volume, and about 2% salt or base by weight.

The selected anion exchange resin may include a macro-porous, strongbase, anion exchange resin. The separation and recovery process may beconfigured to maximize recovery of optimized regenerant solution andminimize volume of concentrated desorbed PFAS. The separation andrecovery process may include one or more of evaporation, distillationand membrane separation. The evaporation or vacuum distillation mayinclude condensing the spent regenerant solution. The separation andrecovery process may include removing carryover PFAS to provide apurified reclaimed solvent for reuse. The separation and recoverysubsystem may include creating an ultra-concentrated PFAS waste productand a solution of concentrated salt or base and water for reuse.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Other objects, features and advantages will occur to those skilled inthe art from the following description of a preferred embodiment and theaccompanying drawings, in which:

FIG. 1 shows an example of a typical PFAS with a hydrophobic non-ionictail and an anionic head;

FIG. 2 shows a three-dimensional view depicting the complexthree-dimensional structure of a typical anion exchange resin beadshowing examples of positively charged exchange sites of the resin beadbinding to negatively charged hydrophilic heads of PFAS molecules, andthe hydrophobic carbon-fluorine tails of the PFAS adsorbing to thehydrophobic backbone of the resin bead;

FIG. 3 is a schematic block diagram showing the primary embodiments ofone embodiment of sustainable system and method for removing andconcentrating PFAS from water; and

FIG. 4 is a block diagram showing the primary steps of one embodiment ofthe sustainable method for removing and concentrating PFAS from water.

DETAILED DESCRIPTION OF THE INVENTION

Aside from the preferred embodiment or embodiments disclosed below, thisinvention is capable of other embodiments and of being practiced orbeing carried out in various ways. Thus, it is to be understood that theinvention is not limited in its application to the details ofconstruction and the arrangements of components set forth in thefollowing description or illustrated in the drawings. If only oneembodiment is described herein, the claims hereof are not to be limitedto that embodiment. Moreover, the claims hereof are not to be readrestrictively unless there is clear and convincing evidence manifestinga certain exclusion, restriction, or disclaimer.

As discussed in the Background section, anion exchange resins are highlyeffective at removing PFAS from water because of the multiple removalmethods involved. The molecular structure of most PFAS compounds can bebroken into two functional units including the hydrophobic non-ionic“tail,” comprised of the fluorinated carbon chain and the hydrophilicanionic “head,” having a negative charge. FIG. 1 shows an example of atypical PFAS 10 with hydrophobic non-ionic tail 12 and hydrophilicanionic head 14, in this example, a sulfonate group, although anionichead 14 may be a carboxylate group or similar type group.

Anion exchange resins are essentially adsorbents with anion exchangefunctionality. The resin beads are typically composed of neutralcopolymers (plastics) that have positively charged exchange sites. FIG.2 shows an example of the complex three-dimensional structure of atypical onion exchange resin bead 16 with positively charged exchangesites exemplarily indicated at 18. Anion exchange resins tend to beeffective at removing PFAS from water because they take advantage of theunique properties of both the anion exchange resin bead and theperfluorinated contaminants, or PFAS, using a dual mechanism ofadsorption and anion exchange. For example, hydrophobic carbon-fluorinetail 12, FIGS. 1 and 2, of PFAS 10 adsorbs to the hydrophobic backboneon anion exchange resin 16, FIG. 2, comprised of cross-linkedpolystyrene polymer chains, exemplarily indicated at 20 anddivinylbenzene cross-links exemplarily indicated at 22. Thenegatively-charged hydrophilic heads 24 (sulfonate groups) or 26(carboxylate groups) of PFAS 10 are attracted to positively-chargedanion exchange sites 18 on anion exchange resin bead 16. The negativelycharged heads 24, 26 of PFAS 10 displaces exchangeable inorganic counterion 38, e.g., a chloride ion which is provided on anion exchange bead 18when it is manufactured. The hydrophobic, uncharged carbon-fluorinetails 12 are adsorbed to the uncharged hydrophobic backbone comprised ofpolystyrene polymer chain 20 and divinylbenzene crosslink 22 via Van derWaals forces as shown.

Depending on the specific properties of both resin bead 16 and the PFAS10, this dual mechanism of removal may be highly effective at removingPFAS from water and certain anion exchange resins have very high removalcapacity for PFAS from water.

While the dual mechanism of PFAS removal discussed above may be highlyeffective at removing PFAS from water because the adsorption of thehydrophobic tails of the PFAS to the hydrophobic backbone of the anionresin exchange bead, it also makes resin regeneration and reuse moredifficult. A high concentration of a brine or base solution, e.g., asolution of a salt, such as NaCl, and water, or a solution of a base,such as NaOH and water, may be used to effectively displace the anionichead of the PFAS from the anion exchange site of the anion exchangeresin bead, but the hydrophobic carbon-fluorine tail tends to stayadsorbed to the resin backbone. Similarly, an organic solvent, e.g.,methanol or ethanol, may be used to effectively desorb the hydrophobictail from the backbone, but then the anionic head of the PFAS staysattached to the resin anion exchange site. Research to date hasdemonstrated that effective regeneration techniques must overcome bothmechanisms of attraction. Solutions combining organic solvents and asuit or base, such as NaCl or NaOH, have shown the most successfulresults to date, e.g., as disclosed in Deng et al., 2010, andChularueangaksorn et al., 2013, discussed in the Background section.Other research has focused on using combinations of ammonium salts,including ammonium hydroxide and ammonium chloride, e.g., as disclosedby Conte et al., Polyfluorinated Organic Micropollutants Removal fromWater by Ion Exchange and Adsorption, Chemical Engineering Transactions,Vol. 43 (2015), incorporated by reference herein.

There is shown in FIG. 3, one embodiment of sustainable system 100 forremoving and concentrating PFAS from water. System 100 includes anionexchange vessel 102 including a selected anion exchange resin therein,exemplarily indicated at 104, configured to remove PFAS from flow ofwater 106 contaminated with PFAS. System 100 also includes line 108which is configured to introduce flow of water 108 contaminated withPFAS into anion exchange vessel 102 such that the PFAS binds to selectedunion exchange resin 104 and are removed from the water to provide flowof treated water 116. In one example, selected anion exchange resin 104is preferably configured to be small, e.g., about 0.5 mm to about 1 mmdiameter beads made of an organic polymer substrate or similar materialwhich is preferably porous and provides a high surface area. Exemplaryselected anion exchange resins may include Dow® AMBERLITE™, IRA958 Cl,DOWEX™ PSR-2, Dow® XUS-43568.00, and similar type anion exchange resins.

System 100 also includes regenerant solution line 110 coupled to anionexchange vessel 102 configured to introduce optimized regenerantsolution 112 into anion exchange vessel 102 to remove the PFAS fromanion exchange resin 104 to regenerate anion exchange resin 104 andgenerate spent regenerant solution 120 in line 122 comprised of removedPFAS and optimized regenerant solution. In one example, optimizedregenerant solution 112 is made in regenerant solution make-up tank 114coupled to regenerant solution line 110 as shown. In one designoptimized regenerant solution 112 preferably includes a mixture of asalt or base, e.g., sodium chloride (NaCl) or sodium hydroxide (NaOH), asolvent and water. In one example, the solvent may include an alcohol orsimilar type solvent. In one example, optimized regenerant solution 112includes about 50% to about 90% methanol by volume, about 10% to about50% water by volume, and about 1% to about 5% salt or base by weight. Inanother example, optimized regenerant solution includes about 70%methanol by volume, about 28% water by volume, and about 2% salt or baseby weight. As discussed above, preferably, selected anion exchange resin104 and regenerant solution 112 removes PFAS from water by a dualmechanism including desorption and ion exchange. For ion exchangeremoval of PFAS from selected anion exchange resin 104, the anion of thesalt or base, e.g., chloride of the NaCl or the hydroxide group of NaOHof optimized regenerant solution 112 displaces the hydrophilic heads 24or 26, FIG. 2, of PFAS 10 on exchange sites 18 of anion exchange resin16 due to the high concentration of the anions in optimized regenerantsolution 112. For desorption, the solvent, e.g., an alcohol, such asmethanol, ethanol or similar type alcohol of the optimized regenerantsolution 112 displaces hydrophobic carbon tails 12 of the PFAS 112bonded to the backbone of anion exchange resin 16 due to the highconcentration of the solvent in optimized regenerant solution 112. Theresult is system 100 and efficiency removes both large and small chainPFAS from water.

In one example, the PFAS removed by anion exchange resin 14 may includePerfluorobutyric acid (PFBA), Perfluoropentanoic acid (PFPeA),Perfluorobutane sulfonate (PFBS), Perfluorohexanoic acid (PFHxA),Perfluoroheptanoic acid (PFHpA), Perfluorohexane sulfonate (PFHxS), 6:2Fluorotelomer sulfonate (6:2 FTS), Perfluorooctanoic acid (PFOA),Perfluoroheptane sulfonate (PFHpS), Perfluorooctance sulfonate (PFOS),Perfluorononanoic acid (PFNA), 8:2 Fluorotelomer sulfonate (8:2 FTS).

System 100 also includes the separation and recovery system 124 coupledto line 122 which recovers optimized regenerant solution 120 for reuseas reclaimed regenerant solution 126 by line 128 coupled to line 110 andpreferably to regenerant solution makeup tank 114. In one design,separation and recovery subsystem 124 provides reclaimed solvent 132 byline 128 as shown and solution 136 of concentrated PFAS, salt or base,and water by line 138 which is coupled to line 128 as shown. The PFAS insolution 136 is removed (discussed below) to provide solution 152 ofconcentrated salt or base and water output by line 138 coupled to line128. Thus, reclaimed regenerant solution 126 preferably includesreclaimed solvent 132 and reclaimed salt or base and water.

In one design, separation and recovery subsystem 124 may includeevaporation subsystem 130. In this example, spent regenerant solution120 is subjected to evaporation by evaporation subsystem 130 to producereclaimed solvent 132 output to line 128 and solution 136 ofconcentrated desorbed PFAS, salt or base and water. Condenser 140 may beutilized to condense reclaimed solvent 132. In another example,separation and recovery subsystem 124 may include one or more of adistillation subsystem 142 and/or a membrane separation subsystem 144which similarly produce reclaimed solvent 132 for reuse by lines 128 and110 and solution 136 of concentrated PFAS, salt or base, and water.

In one example, separation and recovery subsystem 124 may furtherinclude solvent purification subsystem 141 coupled to line 128 whichremoves carryover PFAS from separation and recovery subsystem 124 andprovides purified reclaimed solvent 144 in line 128 for reuse asregenerant solution 112 via regenerant solution makeup tank 114 andregenerant solution line 110. In one example, solvent purificationsubsystem 141 is a smalt vessel, e.g., vessel 160 shown in caption 162as shown having anion exchange resin 104 therein which removes carryoverPFAS in line 134 to create concentrated PFAS in the vessel. When vessel160 becomes saturated with PFAS, it can be removed and taken off-sitefor destruction.

Separation and recovery subsystem 122 may also include super-loadingrecovery subsystem 150 coupled to line 138 output by separation andrecovery subsystem 124 having solution 136 of concentrated PFAS, salt orbase, and water. Superloading recovery subsystem 150 creates ultraconcentrated PFAS waste product adsorbed to anion exchange resin 104 andconcentrated salt or base or caustic water solution 152 purified forreuse. Super-loading recovery subsystem 150 preferably provides solution152 of concentrated salt or base and water coupled to line 128 for reuseas regenerant solution 112 via regenerant solution makeup tank 114 andregenerant solution line 112. In one example, superloading and recoverysubsystem 150 is a small vessel, e.g., vessel 170 in caption 172 asshown having anion exchange resin therein which providesultra-concentrated PFAS on anion exchange resin 104 and outputs solution152 of concentrated salt or base and water. When vessel 170 becomessaturated with PFAS, it can be removed and taken off-site fordestruction. The small size and high concentration of PFAS reduces costsassociated with removal of PFAS from water.

System 100 also preferably includes sample lap 156 or 158 as shown fortesting the level of PFAS in treated water 116. When PFAS are detectedin treated water 116, it means anion exchange resin 104 in vessel 102has been saturated with PFAS attached to anion exchange resin 104 andanion exchange resin 104 need to be regenerated.

The sustainable method for removing concentrated per- andpolyfluoroalkyl substances (PFAS) from one embodiment of this inventionmay include selecting an anion exchange resin configured to move PFASand provide clean, treated water, step 200, FIG. 4. The selected anionexchange resin is then added to an anion exchange vessel, step 202. Aflow of water contaminated with PFAS is introduced to the anion exchangevessel such that the PFAS bind to the selected anion exchange resin andare thereby removed from the water, step 204. An optimized regenerantsolution is introduced to the anion exchange vessel to desorb PFAS fromthe union exchange resin thereby regenerating the anion exchange resinand generating a spent regenerant solution comprised of desorbed PFCsand the optimized regenerant solution, step 206. The spent regenerantsolution is then subjected to a separation and recovery process torecover the optimized regenerant solution for reuse and separate andconcentrate the removed PFAS.

The result is that system 100, and the method thereof for removing andconcentrating PFAS from water, efficiently and effectively removes PFASfrom water, regenerates the anion exchange resin and then concentrates,or ultra concentrates, the desorbed PFAS with a solvent purificationsubsystem and/or on super loading recovery subsystem in small vesselsthat can be inexpensively disposed of. Thus, system 100 and the methodthereof provides a sustainable system and method for concentrating andremoving PFAS from water and regenerating the selected anion exchangeresin, which significantly reduces the cost to remove PFAS from waterbecause it generates less toxic waste than conventional and knownmethods for removing PFAS. The separated and concentrated orultra-concentrated PFAS is easier and less expensive to handle andtransport. System 100 and the method thereof efficiently reclaims thesolvent, salt or base, and water from the spent regenerant solutionwhich further reduces cost.

Although specific features of the invention are shown in some drawingsand not in others, this is for convenience only, as each feature may becombined with any or all of the other features in accordance with theinvention. The words “including”, “comprising”, “having”, and “with” asused herein are to be interpreted broadly and comprehensively and arenot limited to any physical interconnection. Moreover, any embodimentsdisclosed in the subject application are not to be taken as the onlypossible embodiments. Other embodiments will occur to those skilled inthe art and are within the following claims.

In addition, any amendment presented during the prosecution of thepatent application for this patent is not a disclaimer of any claimelement presented in the application as filed: those skilled in the artcannot reasonably be expected to draft a claim that would literallyencompass all possible equivalents, many equivalents will beunforeseeable at the time of the amendment and are beyond a fairinterpretation of what is to be surrendered (if anything), the rationaleunderlying the amendment may bear no more than a tangential relation tomany equivalents, and/or there are many other reasons

1. A system for reducing an amount of a toxic spent regenerant solutionproduced by a system which removes per- and polyfluoroalkyl substances(PFAS) from contaminated water, the system comprising: a concentrationsubsystem configured to separate and concentrate the PFAS in thecontaminated water to produce the toxic spent regenerant solution; and aseparation and recovery subsystem configured to receive the toxic spentregenerant solution, the separation and recovery subsystem including atleast one of a distillation subsystem, an evaporation subsystem, or amembrane separation subsystem, at least one of the distillationsubsystem, the evaporation subsystem, or the membrane separationsubsystem configured to concentrate the PFAS, water, and salt in thetoxic spent regenerant solution to reduce the amount of toxic spentregenerant solution.
 2. The system of claim 1 in which the concentrationsubsystem includes an anion exchange vessel including an anion exchangeresin therein configured to receive a flow of the contaminated watersuch that the PFAS in the contaminated water bind to the anion exchangeresin to remove PFAS from the contaminated water and configured toreceive a regenerant solution comprising a mixture of a salt, a solventand water to regenerate the anion exchange resin and produce the toxicspent regenerant solution.
 3. A method for reducing an amount of a toxicspent regenerant solution produced by a method which removes per- andpolyfluoroalkyl substances (PFAS) from contaminated water, the methodcomprising: separating and concentrating the PFAS in the contaminatedwater to produce the toxic spent regenerant solution; and subjecting thetoxic spent regenerant solution to a separation and recovery processincluding at least one of a distillation process, an evaporationprocess, or a membrane separation process, at least one of thedistillation process, the evaporation process, or the membraneseparation process configured to concentrate the PFAS, water, and saltin the toxic spent regenerant solution to reduce the amount of toxicspent regenerant solution.
 4. The method of claim 3 in which theseparating and concentrating the PFAS includes introducing a regenerantsolution comprising a mixture of a salt, a solvent, and water to ananion exchange resin to remove the PFAS from the anion exchange resin toregenerate the anion exchange resin and generate the toxic spentregenerant solution.